Heroku-16 and Heroku-18 Stack Images Updated

Change effective on 01 June 2020

We have updated the heroku-16 and heroku-18 stack images to pick up security fixes and updates in upstream packages. The new stack images will be rolled out automatically over the next 24 hours. You do not need to redeploy your app or manually restart your dynos.

This release includes an update of the ca-certificates package, which removes the expired AddTrust External Root CA certificate. This prevents SSL verification failures when using older clients (such as openssl older than v1.1.1) to connect to servers that are serving legacy certificate chains.

See this Dev Center article for an overview of the packages available in each stack image.